Firstly, I must say this SCP is very busy. Especially for your first SCP, it's best to pick on one major effect and focus on that one. That doesn't mean there haven't been successful SCPs (new or not) that cause more than one effect - just that your's does so a little too busily.

I'm not sure this would be Keter class, either. Elucid, maybe, since the way it breaches is based on people passing news of it along, and that may very well happen, but the item itself can be shoved in any old locker, with a false document set up to prevent all but those who need to knowing what it is, knowing it.

I don't see the link between a bit of paper and psychosis that leads to death. I'm also not a big fan of death as a quick cop out in a SCP - it often feels like maybe the writer is going for the worst thing they can think of, unless they write expunged, which may led people to use their imagination more, but for me, when

kill and [REDACTED]

are together, it often makes me think the writer wants us to think of rape, not think of something so bad that can be done either with or as well as killing.

Why does the paper have to be in a soundproof chamber? Maybe I missed it, but I thought it was the resulting subjects that made so much noise it was dangerous, not the paper. Again, just shoved it in any old containment locker, make sure it's locked, and make up a cover story for what is inside - as far as the actual paper goes, that's good enough containment.

Grammar isn't too bad, nothing is jumping out at me as awful, though the clinical tone could use some work - instead of a 'small' piece of paper, you should note its dimensions. That means if someone knows about it, they can't decide to be a dick and write 'PerfectIT' on a piece of paper to freak people out and cause panic. Additionally, it's best to black box out numbers or words you don't want to share in the main document, rather than use [REDACTED] (though that is still acceptable as far as I'm aware) or X - just a little thing.

Majorly, to me, whilst not written poorly, it's not an engaging SCP. SCPs that make people go mad for seemingly little to no reason are a tricky thing to do without a strong narrative, and this just doesn't seem to have a strong narrative. It's a random item (this time, very random; still not sure what paper has to do with all this) that causes insanity and death.

You could probably make this work better somehow. I quite like the idea of a piece of paper with just the words 'Perfectit' written on it doing something, I'm just not sure all this links together. Additionally, I know we've got other SCPs who transfer their effect by talking about them, and I'm fairly sure we have SCPs who drive people insane/kill people when they read the text.